The present invention pertains to light diffusing elements provided in intimate optical contact with other surfaces. More particularly, the present invention pertains to optical elements having excellent forward scattering properties and which exhibit low backscatter, and which can further provide adhesive properties.
Diffusion of light is a highly useful phenomenon that finds many applications in optical systems. For example, liquid crystal or other displays often use a diffuser to increase viewing angle of the device and to make unwanted intensity variations less visible to the viewer. Diffusers can be incorporated into optical systems by adding an additional diffuser component to the system, or, in some cases, by incorporating diffusive properties into an existing component by, for example, etching or sandblasting a surface of an existing optical component. Adding additional components to an optical system has the disadvantage of introducing additional absorption and creating additional interfaces that can reflect light, thereby causing loss of illumination and other forms of image degradation. On the other hand, incorporating a diffusing layer into an existing component in the system complicates component design, adds manufacturing steps, and can have an adverse effect on performance and on product yield during manufacturing.
The present invention provides an optical component including a structured polymer layer. In one embodiment, the optical component is useful to direct backreflected ambient light to a peak angle that is different than a glare peak. The optical component includes a mirror surface, the structured polymer layer including one side having structured elements, and a filler layer adjacent to the side of the structured polymer layer having the structured elements. The filler layer fills in the structured elements and has one substantially planar side. The filler layer has a refractive index Nf, the structured polymer layer has a refractive index of Ns, and Ns is different from Nf. The ambient light that is backreflected from the mirror surface is directed to a peak angle that is different from a glare peak angle of the optical component.
In one embodiment of the optical component, the difference between Ns, and Nf is at least 0.15. The value of Ns may be greater than Nf. In one embodiment, Ns is greater than or equal to about 1.34 and less than or equal to about 1.63. Nf may be greater than or equal to about 1.35 and less than or equal to about 1.49.
In one embodiment, the filler layer may be a diffusing material or a diffuse adhesive material. The optical component could include a diffusing layer that may be adjacent to the filler layer.
In another embodiment, the present invention provides a display device including a first and second polarizer, a liquid crystal layer below the first polarizer, a mirror surface below the liquid crystal layer, and a structured polymer layer comprising one side having structured elements. The display device also includes a filler layer adjacent to the side of the structured polymer layer having the structured elements, the filler layer filling in the structured elements and having one substantially planar side. In one alternative, the structured polymer layer and filler layer are between the first and second polarizers. The display device may be configured so that the filler layer has a refractive index Nf, the structured polymer layer has a refractive index of Ns, Ns is different from Nf. In one embodiment of the display device, ambient light that is backreflected from the mirror surface is directed to a peak angle that is different from a glare peak angle of the optical component.
According to another embodiment of the present invention, a display device includes a polarizer, a liquid crystal layer below the polarizer, a mirror surface below the liquid crystal layer, and a structured polymer layer above the liquid crystal layer. The structured polymer layer has one side having structured elements. The display device also includes a filler layer adjacent to the side of the structured polymer layer having the structured elements, the filler layer filling in the structured elements and having one substantially planar side. The filler layer has a refractive index Ns and the structured polymer layer has a refractive index of Ns, Ns is different from Ns. The structured polymer layer and the filler layer are between the polarizer and the mirror layer. The ambient light that is backreflected from the mirror surface is directed to a peak angle that is different from a glare peak angle of the optical component.
According to another embodiment of the present invention, a display device includes a polarizer, a liquid crystal layer below the polarizer, a mirror surface below the liquid crystal layer, and a structured polymer layer between the liquid crystal layer and the mirror surface, where the structured polymer layer includes one side having structured elements. The display device also includes a filler layer adjacent to the side of the structured polymer layer having the structured elements, the filler layer filling in the structured elements and having one substantially planar side. The filler layer has a refractive index Nf and the structured polymer layer has a refractive index of Ns, and Ns is different from Nf. The structured polymer layer and the filler layer are between the polarizer and the mirror layer. Ambient light that is backreflected from the mirror surface is directed to a peak angle that is different from a glare peak angle of the optical component.